In the last years, concolic testing, a technique combining concrete and symbolic execution for the automated generation of test cases, has gained increasing popularity. Concolic testing tools are initialized with expressions on concrete input data. But instead of just evaluating them, they additionally collect symbolic information along specific execution paths. This information can be used to systematically compute alternative inputs exploring yet unvisited paths. In this way, test cases can be generated covering all branches of a given program. The first concolic testing tools have been developed for imperative languages analyzing code at a very low level. Recently, there have been also some approaches investigating the concolic execution of declarative languages. In this work, we discuss the application of concolic testing to the functional logic language Curry. More precisely, we present ccti, a concolic interpreter which is adapted for the automated generation of test cases for both purely functional and non-deterministic programs.